Method of constructing a threaded bung fixture in a wall of a sheet metal container



July 9, 1940. L. B. WACKMAN ,56

METHOD OF CONSTRUCTING A THREADED BUNG FIXTURE v IN A WALL OF A SHEET METAL CONTAINER Filed Jan. 24, 1939 I 2 Sheets-Sheet l y 19.40. L. B. WACKMAN 07,564

METHOD OF CONSTRUCTING' A THREADED BUNG FIXTURE IN A WALL OF A SHEET METAL CONTAINER Filed Jan. 24, 1939 2 Sheets-Sheet. 2

Patented July 9, 1940 UNITED STATES PATENT OFFICE METAL CONTAINER Louis B. Wackman, Richmond Heights, Mo. Application January 24, 1939, Serial No. 252,560

6 Claims.

This invention relates to a method of constructing a threaded bung fixture in a wall of a sheet metal container such as an oil drum or barrel, and pertains particularly to the application and use of the sheet metal wall stock for a major part of the fixture and in which part the threads of the fixture are formed.

This improved method has been found to be one of the methods which may be applied in making the threaded bung fixture for sheet metal containers, shown in my companion application filed of even date herewith, the purpose of the methodand the apparatus of the companion application being to provide a bung fixture having the threads of the bung hole formed in an integral part of the sheet metal stock of the container.

As is well known, sheet metal containers heretofore have structures of threaded bung holes which are either welded to a container wall or are pressed in the wall by crimp stamping and the like. Of these two structures, that which is welded in the container wall has been found to be preferable by reason of being integrally joined therewith so as to be rigidly held against being disturbed by wrench turning on the closure plug of the bung hole structure. The pressed-in type of bung hole structure it has been found, quite often becomes loosened by wrench operation on the closure plug thereof, thereby disturbing the sealing gasket required in the pressed-in structure.

This improved method therefore goes to the provision of means to thread-form a part of the wall stock of a sheet metal container, to represent and be used as a hung fixture and with reenforcing means for the thread-formed part so that the bung fitting constructed by this method will have the unified character of the weldedon bushing by reason of the thread-formed part being a part of the wall stock, and consequently is an integral part of the wall stock.

"In view of the foregoing, it is a primary purpose of the invention to provide a method of constructing a bung fixture in an integral part of a wall of a sheet metal container and of threading the integral part.

It is another object of the invention to apply and form reenforcing means for the threaded part of the bung hole fitting.

A further object is to change the formation of a part of a wall for a sheet metalcontainer and to reenforce the re-formed part during forming of screw threads thereon.

Still another object is to provide an annular extending portion from a sheet metal wall for a container and to secure a pre-formed collar over said annular portion and to reshape the. annular portion in conformity with theinner periphery of the collar.

Another still further object is to construct a bung hole fitting in the material of a sheet metal wall for a container and to provide an interiorly threaded collar to form part of the fitting and to press portions of the material into the. threads of the collar.

Other objects and advantages will appear as this description progresses and by reference to the drawings, in which-- Figure 1 is a transverse verticalsectional elevation taken through a fragmentary portion of a metal container wall and the bung fixture constructed by this improved method, and the figure including a cooperable closure plug and a sealing cap mounted in secured positions over the fixture.

Figure 2 is a fragmentary sectional elevation of the bung fixture illustrated in Fig. 1, with the exception of the fixture showing a modification of the clamping bead for the sealing cap.

Figure 3 is a plan elevation of a fragmentary portion of a sheet metal container wall showing a first step in re-forming that portion of the wall for providing the bung fixture.

Figure 4 is a transversevertical sectional elevation taken on the line 4-4 of Fig. 3.

Figure 5 is a plan elevation of a fragmentary portion of a sheet metal containervwall showing a second step in the operation on the wall.

Figure 6 is a transverse vertical sectional elevation taken on the line 6-6 of Fig. 5.

Figure '7 is a plan elevation of a fragmentary portion of a sheet metal container wall showing the third step in the operation on the wall.

Figure 8 is a transverse vertical sectional elevation taken approximately on the line 8-8 of Fig. '7, showing'the completion of the formation of an extending neck in the container wall.

Figure 9 is a transverse vertical sectional elevation of an interiorly threaded collar which is used both in the construction of the bung fixture and as a permanent reenforcement thereto.

Figure 10 is a fragmentary plan elevation of a portion of the collar shown in Fig. 9.

Figure 11 is a transverse sectional elevation through the pre-formed neck and the collar shown in Fig. 9 loosely mounted thereover. in readiness for being secured together.

Figure 12 is a transverse sectional elevation similar to Fig. 11 after the securing operation-has been effected.

Figure 13 is a transverse vertical sectional elevation of the secured together collar and neck and showing the thread forming operation by a thread rolling tool.

Figure 14 is a transverse vertical sectional elevation of the completely formed and assembled bung fixture which is permanently secured to a container wall.

Figure 15 is a fragmentary plan elevation of Fig. 14.

Referring by numerals to the accompanying drawings, numeral I6 designates a fragmentary portion of a sheet metal container wall in which the bung fixture is formed and constructed, and in the first operation a circular raised portion I! is formed in the wall. as shown in Figs. 3 and 4. The next operation is in punching a concentric opening i8 in the raised portion H, as shown in Figs. 5 and 6, and the following and third operation is in mushrooming and expanding the material of the raised portion surrounding the opening l8 into a straight-walled extending neck 20, as shown in Figs. 7 and 8.

Simultaneous with the forming of the neck 20, a surrounding reenforcing embossment H! for the neck is also formed.

For cooperation with the neck 20, a collar 2| is provided, said collar being interiorly threaded at 22 and having an annular enlargement 23 at one end, and said collar on its end 24 having a counter-bored annular seat 25, as shown in Figs. 9 and 10.

The next operation for providing the bung fixture is to mount the collar 2| over the extending neck 20, in the manner as shown in Fig. 11, in readiness for the hanging operation by a flanging tool 26 beneath which the neck 20 and overengaged collar 2| are positioned. It is to be noted that the free or extending end 21 of the neck 20 extends above the collar a sufficient dis tance so that when the flanging tool 26 is downwardly moved, that portion of the neck extending above the collar is outwardly flanged and firmly seated in and on the seat 25 of the collar, in the manner as shown at 28 in Fig. 12. The neck 20 is then in readiness for having threads formed therein.

For forming the threads in the neck 20, the collar 2| and the threads 22 thereof are used as amatrix or die tool for this purpose, and for carrying out the thread forming operation the bung fixture so far constructed and as shown in Fig. 12, is positioned beneath a thread rolling tool 29 so that the pressing rollers 30 of the tool which are disposed in planes suitable for the pitch of the threads 22 of the collar, can be lowered and fed into the neck 20 in a manner so as to follow the contour of the grooves of the threads 22, as shown in Fig. 13, so that the sheet material forming the neck 20 will be pressed. swedged or rolled into the teeth 22 in conformity therewith.

The flanging-over of the extending end of the neck 20 on the upper end of the collar 2|, provides a rounded annular shoulder at the upper end or mouth of the neck, which facilitates the introduction of the lead roller of the plurality of rollers 3 0 of the rolling tool 29 in-to the neck for following the contour of the threads 22 of the collar 2|.

After the rollers 30 of the tool 29 have traveled throughthe neck, the threading operationljhereof will have been completed, thus completing the constructed and assembled bung fixture as shown in Figs. 14 and 15, with the'closure plug engaging threads 3| formed on the neck 20 which is integral withthe container wall I6.

After a sheet metal container has been assembled ready for use with bung fixtures constructed in a wall or walls thereof by this improved method, most any kind of closure plugs may be used but for the purposes. of this disclosure, a closure plug 32 is provided said plug having the exteriorly formed threads 33 for threading cooperation with the threads 3| of the neck 20 of the bung fixture and the plug 32 carrying a gasket 34 beneath the flange 35 thereof, said gasket when the plug is securely seated in the bung fixture, being compressed in seal-tight engagement in over-lapping relation on the flange 28 of the neck 20 and the end 24 of the collar 2|. Obviously, the gasket 34 is only required to form a seal between the flange 35 of the plug 32 and the flange 28 of the neck 20 of the bung fixture, for

preventing any seepage which may occur between,

the threads of the plug and the neck 20.

The annular enlargement 23 of the collar 2| is beveled on its underside for providing crimping securance for the lower end36 of the side wall 31 of a sealing cap 38 which may be. mounted over the plug and the bung fixture, as shown in Fig. 1, as may be required.

In the use of a bung fixture constructed under this method, it is obvious that by reason of the essential part thereof being the neck 20 which is integral with the container wall and the same being reenforced by the matrix collar 2|, abung fixture of the strength and capacity of the heretofore welded-on bung fixtures, is provided, and.

in consequence, wrenching strains imparted to the closure plug can in no way disturb or effect a bushing made by this improved method, as the same when completed, is obviously homogeneous in character.

In the use of the pressed-in type of bung fixture, it is Well known that severe wrenching strains on the plug for loosening or securing it, often loosens the crimped-in securance thereof, and further the threads of pressed-in bung fixtures often become bent and distorted during the assembly of the fixture in the container wall. In following applicant's improved method of bung fixture construction, it is clear that inasmuch as the threading at 3| on the neck 20 isthe last and completing operation on the fixture, distortion of the threads is obviously eliminated.

It is also to be noted that the bung fixture when constructed by this improved method, provides for the collar 2| being rigidly locked to the neck 20 by the threads 22 of the collar being interlocked with the threads 3| of the neck which will prevent the turning of the collar in one direction,

and the interlocking of the flange 28 of the neck in the seat 25 of the collar will prevent the collar being turned on the neck in the other direction.

It is also important to note that there are no gaskets used in the construction of bung fixtures made in practicing this improved method, and

True. the plug gasket as shown at 34,,

erosion through repeated uses thereof, but as th'is'gasketisalways available for inspection, it

can be readily repIacedf' In the event of breakage occurring in diam fixture constructed under this improved method h'y severe wrenching strains being given to the fixture, such breakage or fissure forming would 1 develop in the wall stock at a point adjacent flar-ging tool 26 and the threadrolling tool 28 which are shown for the purposes of illustration, it is obvious that other types of tools may be used and particularly with respect to the thread rolling tool where a collapsible threading tool may be used in lieu thereof.

The illustration of Fig. 2 shows the embodiment of an annular bead 39 whlch may be used instead of the beveled embossment shown in Fig. 1, for cap crimping securance, where required.

While an annular reenforcing embossment 19 from which the neck 20 is extended, is shown,

other designs of reenforcing embossment may be made and used, such as the embossment having radial projections 40, as shown in dotted lines in Fig. 15.

While I have described one embodiment of my invention with some particularity, obviously many other embodiments thereof may occur to those skilled in the art to which it appertains. I, therefore, do not limit myself to the precise details described, but claim as my invention all variations and modifications coming within the scope of the subjoined claims.

What I claim is:

1. The method of constructing a bung fixture in a sheet metal wall for a container consisting of forming an extending neck from the wall, of freely mounting an interiorly threaded collar over the neck, of flanging the free end of the neck over the outer end of the collar to hold the neck and collar from turning relative to each other during swedging of portions of the neck into the groove of the thread of the collar, and then swedging portions of the neck into the thread groove of the collar.

2. The method of constructing a bung fixture in a sheet metal wall for a container consisting of stamping an opening in the wall, of extruding an outwardly extending neck from the surrounding material of the opening in the wall, of freely mounting an interiorly threaded collar over the neck, of fianging the free end of the neck over the outer end of the collar to hold the neck and collar from turning relative to each other during outwardly swedging of the wall of the neck into seating conformity with the thread of the collar, and then outwardly swedging the wall of the neck by roller spinning portions of of the collar.

3. The method of constructing a bung fixture in a sheet metal wall for a container consisting of cupping a portion of the wall, of stamping an opening in the cupped portion, of extruding an outwardly extending neck from the surrounding material of the opening in the cupped portion, of freely mounting an interiorly threaded collar over the neck, of fianging the free end of the neck over the outer end of the collar to hold the neck and collar from turning relative to each other during thread forming on the neck, and then roller spinning the thread on the wall of the neck into seating conformity with the thread of the collar.

4. The method of constructing a bung fixture in a sheet metal wall for a container consisting of cupping a portion of the wall, of stamping an opening in the cupped portion, of extruding an outwardly extending neck from the surroundingmaterial of the opening in the cupped portion, of freely mounting an interiorly threaded collar over the neck, of fianging the free end of the neck over the outer end of the collar to hold the neck and collar from turning relative to each other during threading operation on the neck, and then threading'the wall of the neck by successively rolling portions of the neck into seating conformity with the thread of the collar.

5. The method of constructing a bung fixture in a sheet metal wall for a container consisting of stamping an opening in the wall, of extruding an outwardly extending neck from the surrounding material of the opening in the wall, of engaging an interiorly threaded collar having an annular recessed seat formed at one end over the neck, of fianging the free end of the neck with the marginal edge thereof in engagement with the recessed seat of the collar, and of outwardly swedging the wall of the neck into seating conformity with the thread of the collar to form an inner thread on the neck wall.

6. The method of constructing a bung fixture in a sheet metal wall for a container consisting of stamping an opening in the wall, of extruding an outwardly extending neck from the surrounding material of the opening in the wall, of engaging an interiorly threaded collar having an annular recessed seat formed at one end over the neck, of flanging the free end of the neck with the marginal edge thereof in engagement with the recessed seat of the collar, and of roller spinning portions of the neck into seating conformity with the thread of the collar to form an inner thread on the neck wall.

LOUIS B. WACKMAN.

the neck into seating conformity with the thread 

